It is well known to provide a refrigeration system for use with one or more temperature controlled storage devices such as a refrigerator, freezer, refrigerated merchandiser, display case, etc. that may be used in commercial, institutional, and residential applications for storing or displaying refrigerated or frozen objects. For example, it is known to provide a refrigeration system having a refrigerant for direct expansion in a single loop operation to provide cooling to heat exchanger such as an evaporator or chiller. It is also known to provide a secondary liquid coolant loop that is cooled by the chiller and then routed to various storage devices to provide cooling to temperature controlled objects. It is also known to provide temperature controlled storage devices operating at various temperatures. A refrigeration system having improved efficiency and thermal characteristics for use with temperature controlled storage devices operating at various temperatures is provided.